A 55-year-old woman presents to the Emergency department with progressive weakness and numbness in both legs. Her symptoms have developed over the course of a week, and she has also noticed numbness and weakness in her hands, double vision, and weakness in her facial muscles. She has a history of rheumatoid arthritis and was recently diagnosed with diabetes due to long-term steroid use. On examination, she has cushingoid features, restricted left lateral gaze, bilateral facial weakness and dysarthria, reduced tone in the upper limbs, marked weakness of handgrip and wrist flexion/extension bilaterally, absent reflexes, and sensory loss to all modalities extending up to the elbow bilaterally. In the lower limbs, she has flaccid tone bilaterally, some wasting and weakness of the proximal muscles, marked weakness of dorsiflexion and plantarflexion of the foot bilaterally, absent reflexes, and reduced sensation to all sensory modalities extending to the knee bilaterally. Blood tests show normal sodium and urea levels, low potassium levels, elevated creatinine levels, and high HbA1c levels. The erythrocyte sedimentation rate is also elevated, and the lumbar puncture shows elevated CSF protein levels and low CSF glucose levels. How would you initially manage this patient?